It has been known for a number of years to utilize focused energy in the form of heat or electricity to burn or sear skin and underlying tissue in connection with the treatment of various ailments and disease. The practice, known as cauterization, has been particularly useful for the removal of abnormal skin growths. One drawback to the practice has been the generation of foul-smelling materials at the site resulting from the burning of the tissue. Fortunately, the volume of these materials was typically relatively low due to the type of ailments treated by the process. However, where electrocautery is used to seal blood vessels in connection with invasive surgery, the volume of materials generated is substantially increased.
Since the 1970's, lasers have been used in operating rooms to treat a wide variety of ailments. As in the traditional practice of cauterization, the laser was used to burn or sear tissue. However, because the laser was used in larger scale invasive surgery, the amount of materials generated at the site was substantially larger than that from traditional cauterization, with resulting problems related to the volume of the foul-smelling materials and the effect on operating room personnel.
The gas-generation problem has become more prevalent because in a number of surgical applications, lasers have an advantage over conventional scalpel cutting tools in that the laser is a more precise instrument, resulting in less trauma to adjacent tissue. Also, because the heat generated by the laser cauterizes the tissue as it is being cut, there is less blood loss and the healing process is speeded along.
In operation, the laser scalpel performs its cutting function by burning a narrow width of tissue. This process vaporizes moisture in the tissue and creates a smoke plume consisting primarily of water vapor, but which also includes small quantities of potentially hazardous and toxic gases, odor-causing gases, particulate matter, including those of 1 micron or less, and bacteria and viruses.
This smoke generated by the laser scalpel, otherwise known as the laser plume, creates a variety of problems for the surgical operating team. The laser plume obscures the view of the surgeon during cutting. Further, the plume eventually deposits a coating on the mirrors used for viewing the cutting site. The operating room personnel also risk contracting infection by inhaling bacteria and virus from the tissue vaporized by the laser which are carried in the plume. The materials generated by the laser scalpel and carried in the laser plume tend to cause headaches and nausea, and more rarely nosebleeds and vomiting, which in certain instances have forced the operation to be terminated due to the sickness of the personnel. Finally, it has recently been determined that low levels of mutagenic, carcinogenic and toxic agents such as cyanide, formaldehyde and benzene are carried along in the plume.
The volume of the generated laser plume is a function of the power of the laser scalpel. As higher powered lasers are used, increasing amounts of laser plume are generated, consequently increasing the risk and discomfort to the operating team. The major lasers used in the medical and surgical fields utilize the lasing materials Neodymium-Yttrium Aluminum Garnet (Nd:YAG), Carbon Dioxide and Argon.
Early attempts to address the problem of removing the laser plume involved the use of vacuum devices fitted with an activated charcoal filter. These early devices removed the laser plume smoke from the cutting site and improved the surgeon's view of the site. However, the vacuum device could not remove all of the plume generated by high energy laser scalpels. Also, the moisture in the plume would tend to deactivate the charcoal over a period of time. Further, the charcoal filter had little or no effect on reducing the odor.
To meet the new requirements caused by the use of higher powered lasers, LASE Inc., a subsidiary of U.S. Medical Corporation, Cincinnati, Ohio, developed a smoke evacuation system incorporating an activated charcoal filter, a moisture filter before the charcoal filter to prevent deactivation of the charcoal filter, a high efficiency particle absorbing filter for capturing particles as small as 0.12 micron, a larger diameter hose to capture the increased volume of laser plume generated, and a deodorizing cartridge to mask the odor created by the plume. One type of evacuator unit used in laser surgery was the Lase System, from U.S. Medical Corporation, and discussed in U.S. Pat. No. 4,963,134 which is incorporated herein by reference.
In the middle 1980's, clinical studies were conducted which determined that amounts of mutagenic and carcinogenic agents such as cyanide, formaldehyde and benzene, and also traces of compounds such as acetone, isopropanol, cyclohexane, and toluene, are produced during the laser surgery operation. Studies also recently determined that bacteria and viruses in the tissue subjected to laser were carried in the active state in the plume. Smoke evacuation systems employing only activated carbon and a particulate filter are unable to remove the mutagenic agents, bacteria and virus species, and the odor causing species from the plume. Rather, these systems were only able to partially mask the odor causing species in the plume.
The removal of mutagenic and carcinogenic agents and other agents, such as bacteria and odor causing species, from the surgery plume is addressed by a filter device and filtering method which utilize an oxidizing and surface active solution to contact the plume. The device and method are the subject of co-pending application Ser. No. 08/198,480 entitled Surgery Plume Filter Device and Method of Filtering and U.S. Pat. No. 5,288,469, which application and patent are commonly owned with the present application.
The filter device is connected in-line to an evacuation unit which draws a vacuum airstream for capturing the surgery plume. The solution is supplied to the filter device from an external solution source, and specifically is sprayed or pumped from the external source into the airstream being filtered to interact with the airstream and form a foam which continues to rupture or break up and refoam. The foam is contained in the filter device as the airstream flows therethrough, and the contact time of the surgery plume with the foam containing the surface active and oxidizing component is sufficient to break down the mutagenic and carcinogenic agents and odor causing species, and to kill the bacteria and virus in the surgery plume airstream. The filter further utilizes an activated carbon component, for further filtering, such as filtering of organic compounds.
While such filtering devices and methods are quite effective in cleansing a surgery plume of undesirable agents, it has been necessary to accommodate the filtering device with a specifically designed evacuation unit or filter cart. More particularly, such filter devices and methods require that oxidizing solution be introduced into the filtered airstream, and therefore, the evacuation units must include a supply of solution, transfer lines coupling the filter device with the solution supply, and a controlled pumping mechanism for delivering the solution to the filter device. As may be appreciated, the various solution supply components of the evacuation units are subject to wear and failure, and thus must be repaired or replaced. Since the filter requires the solution for proper operation, maintenance and replacement of the solution delivery components are necessary and increase the cost of using the filter. Furthermore, the evacuation units may have to be somewhat larger than conventional units to accommodate the additional equipment.
Additionally, many available evacuation units are designed to draw a vacuum through a dry filter and do not have the capability of delivering solution. Therefore, either the filter cannot be used or the evacuation unit must be retrofitted with a solution delivery system. Retrofitting is not only inconvenient for medical personnel, but improperly retrofitting an existing unit to operate with the filter device may reduce the filter device's effectiveness. As such, the necessity of providing a particular evacuation unit to use the filter device makes the device somewhat impractical and costly for both the manufacturer and suppliers and the end user.
Accordingly, it is an object of the invention to reduce the inconvenience of using a surgery plume filter device or method to remove certain agents from the airstream.
It is another objective to provide a filter device which is readily usable with a variety of different evacuation units or filter carts without retrofitting the particular evacuation unit or the filter device.
It is still another objective to provide a filter device and method that may be effectively utilized to remove harmful and offensive agents from a surgery plume without concern for the particular evacuation unit available or its liquid delivery capability.
It is still another objective to reduce or eliminate maintenance and replacement costs associated with solution delivery systems used in conjunction with the filter device.